The province is reviewing hundreds of prostate exams, and over 1500 other tests, after discrepancies were found in the work of one pathologist.

"We were first made aware of the concern voiced by a urologist at the [Royal Alexandra Hospital], where there seemed to be a difference between what was noted at surgery, and what was included in the pathology specimen," Alberta Health Services President and CEO Dr. Chris Eagle said.

Hundreds of patients will be contacted in the coming days – 159 prostate exams are among the tests being reviewed.

So far, 126 have been reviewed, of those, 51 showed no discrepancies, and 46 of them had minor discrepancies.

However, in 14 of them, the pathologist underestimated the aggressiveness of the cancer, and 15 patients were told they didn't have cancer, when they did.

Dr. Eagle announced the review of the results Friday, and apologized to patients.

"First of all, I want to sincerely apologize for any distress and concern that this incident will have, or has had on patients and families in Alberta," Dr. Eagle said.

"These discrepancies are significant and the change in reporting may impact some patients."

AHS said the doctor in question has since retired, after a long career in the province.

Dr. Eagle said his identity would not be released by AHS.

"We work in an environment where we don't blame or shame the concept of a justice and trust culture."

The Health Quality Council of Alberta and the College of Physicians and Surgeons are now handling the investigation, the two organizations will decide if they will reveal the identity of the doctor in question.

With files from Kevin Armstrong